BMC Kaius 01 Review
Catch a glimpse of the BMC Kaius 01 from across the street and its intentions are immediately clear. A one-piece cockpit with integrated brake hoses, a SRAM Red AXS wireless groupset and a pair of Zipp 303 Firecrests shod with Pirelli’s Gravel H tyre just scream speed.
Until now, BMC have had an interesting gravel/mixed surfaces bike line-up; the Roadmachine X is built to gobble up poor road surfaces and broken tarmac but gets overwhelmed on extended stretches of gravel, and the URS sits at the complete other end of the spectrum with its ultra-compliant frame and even suspension on some models. You might be thinking that the current line up covers all bases, but in recent years a whole new niche has emerged: gravel racing. 4/5
£11350 | Buy from BMC
TL:DR
The BMC Kaius 01 gravel bike represents a new sub genre to to gravel cycling world; focussed on all out speed, the Kaius 01 could be the ultimate race bike for those looking for marginal gains over the rough stuff. . Race might equate to stiff and tiresome to ride for some but BMC have managed to blend compliance and intoxicating speed to create a very fast bike. It’s hilariously expensive but for those chasing seconds over the course of a race it could be worth it.
For
Blisteringly fast over gravel and tarmac
Combines compliance and stiffness
Svelte chassis is a dream to climb
Integrated cockpit is super tidy but functional
Against
Downtube protection wouldn’t go amiss
Tyres won’t be ideal for all situations
Hilariously expensive
Won’t suit rougher terrain
The Lowdown
Gravel Race Bike
7.4kg with bottle cages (size 54)
Zipp 303 Firecrest wheelset
12 speed SRAM red AXS groupset
£11 350
Geomery Adapted from TeamMachine
What even is a gravel race?
Races vary in length from 120km to 300km plus and normally take in a huge amount of elevation; the jewel in the newly crafted gravel crown is Unbound, a 320km race with 3000m of climbing that darts across Kansas. Winning these races requires a heady blend of aero, compliance, weight and stiffness and before the latest crop of gravel race bikes, riders would often have to strike a compromise between characteristics to ensure they made it to the end of the race but with a bike that could respond to an all-out sprint to the line after 320km.
A racing pedigree
Racing is in BMC’s blood, they have designed some of the most successful race bikes in history, their bikes have carried riders to the top steps of Grand Tours, cobbled classics, and multiple Olympic and mountain bike World Cups. Can they turn their hand to the ever evolving mosh pit of gravel and create something truly class leading? We headed out to the stunning hills surrounding Turin to put their new machine to the test.
Starting with a clean slate
BMC were very keen to stress that the Kaius platform was developed from scratch rather than being an evolution of a previous iteration meaning they could start with a blank page and attempt to understand what a gravel race bike really needs to do. Riding fast is just one part of the puzzle but arguably the easiest; deep aerofoil tubes will slip through the air but talk to any engineer and they’ll tell you an aero tube shape is the antithesis of compliance. BMC used extensive CAD modelling to determine the optimal tube shapes and carbon layups to strike a balance between aero and comfort.
Gravel racing is also very attritional on the bike itself, rocks and branches can clout the downtube and it needs to be able to fend them off, but a carbon weave that is strong to impacts wreaks havoc on compliance so once again BMC turned to their computers and came up with the optimal carbon layups to offer durability and comfort. We would have liked to see some form of downtube protection however, especially near the bottom bracket as a rogue rock could do a huge amount of damage if you were unlucky. Even a strip of Heli Tape would suffice and provide a bit more piece of mind.
The outcome of all this CAD work and simulation is a frame that weighs a svelte 910g in size 54 and the complete module with forks, seatpost and integrated cockpit tips the scales at 1785g – ten grams lighter than the tarmac focused TeamMachine.
The fully integrated cockpit is a work of art, all the hydraulic hoses are hidden away under the bar, so the overall look is exception clean, not to mention more aero.
It’s all in the angles
The geometry of the Kaius is very similar to the Roadmachine albeit with 15mm more reach. BMC have counteracted the extra top tube length with a shorter stem on the integrated cockpit; this gives the bike a more planted and stable feel through corners but also maintains responsiveness, something that is critically important when riding and racing on gravel. The bottom bracket is also slightly lower than the Roadmachine to create a feeling of sitting in the bike as opposed to on it which creates a more stable and confidence inspiring platform when riding at speed.
Ride Impressions
It's all well and good examining geometry figures and aerofoil shapes, but what is the Kaius 01 actually like to ride?
In a word – scintillating. Throw a leg over the gently sloping top tube and the Kaius reveals its personality immediately. The fit is racey as one would expect; the front end is reasonably low compared to the ‘traditional’ gravel bike but we didn’t have any discomfort having ridden 200km over 2 days.
Grasp the slender hoods of the SRAM Red shifters and the thing that strikes you immediately is how narrow the handlebars are; the 360mm wide (centre to centre) reduce the frontal area when riding and once we’d come to terms with their narrowness we actually found them very comfortable. The width at the drops flares to 420mm to inspire more confidence at speed and the 12.5 degrees of flare from hoods to drops means there’s plenty of space for your wrists in the drops.
The wide nosed Fizik saddle also meant that we could perch right on the front of it and hunker down into the drops when riding full gas
Begin to crank on the pedals and the stiffness of the bottom bracket area makes itself known; no discernible flex means that is feels like every watt of power leaving your legs is translated directly into forward motion rather than being absorbed by a flexy frame. The Kaius 01 uses a BB86 press fit standard and the extra width afforded heaps of stiffness which was apparent almost immediately.
Some folks will still bemoan the lack of a threaded bottom bracket for easy maintenence but the Kaius is a cutting edge bike and when chasing those extra percentage points of stiffness every little helps. Let’s face it, with a premium price tag, potential owners can probably afford to have their local shop diagnose any creaks that might emerge after a few thousand kilometres.
A little bit of everything
Our test route consisted of a very hilly loop in the hills to the south of Bra with a mix of surfaces from tarmac climbs to technical gravel descents, so it was a perfect testing ground to explore the strengths and weaknesses of the Kaius. BMC had also kindly (or cruelly) entered us into a gravel race to test the bike under race conditions; something that can throw up foibles that would go unnotched when not riding on the limit.
Taking the rough with the smooth
The first thing that leapt out at us was just how smooth the ride was, the handle bar portion of the cockpit uses an aerofoil shape to cut through the air but a side benefit to this that a horizontal aerofoil is a naturally compliant shape; it flexes under load to absorb high frequency vibrations. We’ve ridden gravel bikes with a traditional round handlebar and the BMC cockpit left our arms feeling much fresher at the end of the ride having not been shaken to pieces. Compliance at the rear is similarly impressive over high frequency bumps on account of a D shaped carbon seatpost but on really rough terrain the bike can get thrown around a little but this isn’t a surprise given it’s a rigid carbon frame.
The way the bike gets up to speed and maintains it was also outstanding, a short burst out of the saddle urged the bike down the road with ferocious efficiency and then when settled down into the narrow cockpit the Kaius seemed to be able to hold its speed with ease. On the tarmac sections between gravel the only thing that gave away its gravel persuasions was the slight buzz from the lightly treaded tyres and even that didn’t appear to have an a major impact on speed.
The Kaius 01 was shod with a pair of Pirelli Cinturato Gravel H tyres with were perfect for the hard packed Strade Bianchi and would serve as an excellent all round tyre if your typical routes take in a healthy mix of tarmac and gravel. We could envisage the Kaius 01 to be the definitive one bike garage; a spare pair of wheels with dedicated road tyres and you’d have a very capable road bike that could easily compete with the current crop of super bikes.
Only the best for the Kaius 01
Shifting was taken care of SRAM’s excellent Red AXS wireless groupset, the 42 tooth chainring paired to a 10-44 cassette provided a wide enough spread of gears to get us up some alarmingly steep inclines and small enough jumps between gears to be able to settle into a comfortable cadence on flatter sections. Changing gear was a complete non event; hit the paddle behind the carbon brake leaver and the rear mech quickly and accurately moves the chain. Braking was similarly eventless, huge amounts of power but very easy to modulate on technical descents even from the hoods.
The bike rolls on a pair of Zipp 303 Firecrest carbon wheels. The 303 lineup has been a mainstay of the professional peloton for many years now, first developed to tackle the cobbled classics on the road they are engineered to be tough but also aero thanks to their width and rim profile. Measuring 25mm wide, the 303 Firecrests offer an optimal platform for a wider gravel tyre, offering more support whilst being more aero.
The Kaius can accept up to a 44mm width as measured tyre which offered excellent grip and cushioning. We’d have like to have experimented with lower pressures to dial up the comfort but didn’t want to risk a flat in the heat of the race.
Leave no stone unturned
You might be thinking why the bottle cages deserve a mention and the answer is that they’re not just a pair of bog-standard cages. BMC have christened the concept ‘Aerocore’ and what they’ve done is integrate the cages into the downtube to reduce drag by designing the downtube and cages together as a system. What this means in practice is the cages have a profiled lip to interface smoothly with the downtube; the whole package looks very sleek and no bottles were lost over the course of the rides so there’s no case of form over function here.
Over the course of 200km riding, we did encounter an issue with the seatpost slipping but with a slither of carbon paste and a smidge more than advised torque on the seatpost clamp our issues were alleviated.
We do need to discuss the very large elephant in the room though; the price. The Kaius hit’s the market with a wince inducing price tag of £11 350 for this top-of-the-line model. Now that you’ve picked your jaw off the floor, we’ve got to remember this is a money no object, no holds barred race machine pitched at the very top of the market with a sole focusing of going very fast. BMC have upturned every stone in search of additional speed and compliance and every opportunity to shave grams has been taken.
There will be two further models in the Kaius line, the Two and Three which will share the same frame but lower grade components and a more traditional bar/stem setup. We’d be very keen to ride these models to see how much of the DNA has been inherited by the more attainable models.
Nowadays in the cycling industry it’s rare to ride a bike that has been developed from the ground up, normally there’s a predecessor to compare it to or at least a similar bike in the category.
The Kaius 01 is off the front on a solo breakaway, it looks like a purebred race bike and rides like one too. Everything about it is designed to go fast, the geometry and positioning, the one-piece integrated cockpit and deep section wheels are crying out to be ridden as hard as possible but it won’t leave you feeling like you’ve done 10 rounds in a boxing ring after the finish line.
It won’t be for everyone, look elsewhere if you’re into bikepacking as it has no mounts aside from the bottle cages and you’ll need to have done your yoga to comfortably settle into the racey position for long days in the saddle but if it’s a gravel race bike you’re after, the Kaius 01 could be your very expensive kryptonite.